Hagoromo told us that Madara achieved the Rinnegan by combining the power of both his sons, which creates the Sage's power.
The Sage is giving Naruto and Sasuke his power so they do not need each other's dna/power inorder to awaken the Rinnegan, because they are getting the Sage's power directly from the sorce.
On top of this, Naruto will also have the power of all the Bijuu, which I believe will keep him above Sasuke's power level.
The Sage is giving Naruto and Sasuke his power so they do not need each other's dna/power inorder to awaken the Rinnegan, because they are getting the Sage's power directly from the sorce.
On top of this, Naruto will also have the power of all the Bijuu, which I believe will keep him above Sasuke's power level.